Velocity Reviews > can u explain this code?

# can u explain this code?

kartheeknagasuri@gmail.com
Guest
Posts: n/a

 08-08-2006
my friend gave this code to me..... it is working fine....how come?

please explain me if u can understand.....

#include <stdio.h>
#include <conio.h>

#define _(__,___)\
___##__
_(id,vo) _8(_(
ar,ch)a,_(ar ,ch
)*_2){_(ile,wh) (a
--)_(ntf, pri)("%s"
,_2);}_(id,vo) _1(_
(nt,i) s,_(nt,i) n,
_(nt,i) k=1,_(ar,ch
) *_3="* "){_8 ( k,
"\n");_8(s," ");_8(
n,_3);}_(id,vo) _6(_(nt,i) k,_(nt,i)
l,_(ar,ch) *_9_){_8(k,"\n");_8(l, " ");_(ile
,wh)(*_9_)_(ntf,pri)("%c",*_9_++-12);} _(id,
vo) _(in,ma)(){_(ar,ch) _1_1_[]="cu€" "t,nq"
"€,~qsm~p8",_2_2_[]="X{wm";_(ar,ch) _22[]=
{240,32,0},_4;_1(20,3,6);_1(19,1)
;_1(4,1,0);_1(19,1); _1(1,1, 0,
_22);_1(1,1,0);_1(19,1);
_1(4,1,0);_1(15,;
_1(13,10);_1(0,1,0,"*");_
(or,f)(_4=0;_4<4;_4++) {_1(15+_4*2,
8-_4*2);_(f,i)(_4==0) _1(0,2,0," *");}_(
or,f)(_4=2;_4>=0;_4--)_1(15+_4*2,8-_4*2);_6(3,
26,_1_1_);_6(2,40,_2_2_);_(ile,wh)(!_(it,kbh)());}

Richard Heathfield
Guest
Posts: n/a

 08-08-2006
http://www.velocityreviews.com/forums/(E-Mail Removed) said:

> my friend gave this code to me..... it is working fine....how come?

foo.c:2: conio.h: No such file or directory

Looks like it doesn't work fine after all.

And even if you ignore that, it gets the entry point's return type wrong, so
the behaviour of the program is undefined. There's nothing even remotely

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

Tak-Shing Chan
Guest
Posts: n/a

 08-08-2006
On Tue, 8 Aug 2006 (E-Mail Removed) wrote:

> my friend gave this code to me..... it is working fine....how come?
>
> please explain me if u can understand.....
>
> #include <stdio.h>
> #include <conio.h>
>
>
> #define _(__,___)\
> ___##__
> _(id,vo) _8(_(
> ar,ch)a,_(ar ,ch
> )*_2){_(ile,wh) (a
> --)_(ntf, pri)("%s"
> ,_2);}_(id,vo) _1(_
> (nt,i) s,_(nt,i) n,
> _(nt,i) k=1,_(ar,ch
> ) *_3="* "){_8 ( k,
> "\n");_8(s," ");_8(
> n,_3);}_(id,vo) _6(_(nt,i) k,_(nt,i)
> l,_(ar,ch) *_9_){_8(k,"\n");_8(l, " ");_(ile
> ,wh)(*_9_)_(ntf,pri)("%c",*_9_++-12);} _(id,
> vo) _(in,ma)(){_(ar,ch) _1_1_[]="cu€" "t,nq"
> "€,~qsm~p8",_2_2_[]="X{wm";_(ar,ch) _22[]=
> {240,32,0},_4;_1(20,3,6);_1(19,1)
> ;_1(4,1,0);_1(19,1); _1(1,1, 0,
> _22);_1(1,1,0);_1(19,1);
> _1(4,1,0);_1(15,;
> _1(13,10);_1(0,1,0,"*");_
> (or,f)(_4=0;_4<4;_4++) {_1(15+_4*2,
> 8-_4*2);_(f,i)(_4==0) _1(0,2,0," *");}_(
> or,f)(_4=2;_4>=0;_4--)_1(15+_4*2,8-_4*2);_6(3,
> 26,_1_1_);_6(2,40,_2_2_);_(ile,wh)(!_(it,kbh)());}

Nonportabilities [1] aside, the actual obfuscation here is
fairly simple: #define _(__,___) ___##__ concatenates its two
arguments in reverse. Thus, _(id,vo) gives gives you void,
_(ar,ch)*_2 gives you char*_2 (and so forth).

Tak-Shing

[1] I would leave it to the pedants to enumerate them.

Morris Dovey
Guest
Posts: n/a

 08-08-2006
Tak-Shing Chan (in
(E-Mail Removed) k) said:

| On Tue, 8 Aug 2006 (E-Mail Removed) wrote:
|
|| my friend gave this code to me..... it is working fine....how come?
||
|| please explain me if u can understand.....
||
|| #include <stdio.h>
|| #include <conio.h>
||
||
|| #define _(__,___)\
|| ___##__
|| _(id,vo) _8(_(
|| ar,ch)a,_(ar ,ch
|| )*_2){_(ile,wh) (a
|| --)_(ntf, pri)("%s"
|| ,_2);}_(id,vo) _1(_
|| (nt,i) s,_(nt,i) n,
|| _(nt,i) k=1,_(ar,ch
|| ) *_3="* "){_8 ( k,
|| "\n");_8(s," ");_8(
|| n,_3);}_(id,vo) _6(_(nt,i) k,_(nt,i)
|| l,_(ar,ch) *_9_){_8(k,"\n");_8(l, " ");_(ile
|| ,wh)(*_9_)_(ntf,pri)("%c",*_9_++-12);} _(id,
|| vo) _(in,ma)(){_(ar,ch) _1_1_[]="cu?" "t,nq"
|| "?,~qsm~p8",_2_2_[]="X{wm";_(ar,ch) _22[]=
|| {240,32,0},_4;_1(20,3,6);_1(19,1)
|| ;_1(4,1,0);_1(19,1); _1(1,1, 0,
|| _22);_1(1,1,0);_1(19,1);
|| _1(4,1,0);_1(15,;
|| _1(13,10);_1(0,1,0,"*");_
|| (or,f)(_4=0;_4<4;_4++) {_1(15+_4*2,
|| 8-_4*2);_(f,i)(_4==0) _1(0,2,0," *");}_(
|| or,f)(_4=2;_4>=0;_4--)_1(15+_4*2,8-_4*2);_6(3,
|| 26,_1_1_);_6(2,40,_2_2_);_(ile,wh)(!_(it,kbh)());}
|
| Nonportabilities [1] aside, the actual obfuscation here is
| fairly simple: #define _(__,___) ___##__ concatenates its two
| arguments in reverse. Thus, _(id,vo) gives gives you void,
| _(ar,ch)*_2 gives you char*_2 (and so forth).
|
| Tak-Shing
|
| [1] I would leave it to the pedants to enumerate them.

Ugh, not pretty! With liberal renaming I got:

#include <stdio.h>
#include <conio.h>

void fna(char a,char *s)
{ while (a--) printf("%s",s);
}

void fnb(int k,int l,char *9)
{ fna(k,"\n");
fna(l, " ");
while(*9) printf("%c",*9++-12);
}

void fnc(int s,int n,int k=1,char *t="* ")
{ fna(k,"\n");
fna(s," ");
fna(n,t);
}

void main()
{ char v1[] = "cu?t,nq?,~qsm~p8",
v2[] = "X{wm",
v3[] = { 240,32,0 },
i;

fnc(20,3,6);
fnc(19,1);
fnc(4,1,0);
fnc(19,1);
fnc(1,1, 0,v3);
fnc(1,1,0);
fnc(19,1);
fnc(4,1,0);
fnc(15,;
fnc(13,10);
fnc(0,1,0,"*");
for (i=0; i<4; i++)
{ fnc(15+i*2,8-i*2);
if (i==0) fnc(0,2,0," *");
}
for (i=2; i>=0; i--) fnc(15+i*2,8-i*2);
fnb(3,26,v1);
fnb(2,40,v2);
while (!kbhit()) ;
}

Left as an exercise for the OP to enumerate the problems.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

Keith Thompson
Guest
Posts: n/a

 08-08-2006
(E-Mail Removed) writes:
> my friend gave this code to me..... it is working fine....how come?
>
> please explain me if u can understand.....

"u" doesn't read this newsgroup. If you meant "you", please say so.
Silly abbreviations like "u" for "you" are discouraged here.

> #include <stdio.h>
> #include <conio.h>

>
> #define _(__,___)\
> ___##__

The identifiers __ and ___ are reserved to the implementation.

Leaving that aside, the macro takes two arguments and pastes them
together in reverse order. For example, "_(id,vo)" expands to "void".

> _(id,vo) _8(_(
> ar,ch)a,_(ar ,ch
> )*_2){_(ile,wh) (a

[snip]

It's not worth my time to wade through all that noise. If you're
curious find out if your compiler has an option to show you the output
of the preprocessor. Coment out the #include directives so it doesn't
insert the contents of those headers into the output.

--
Keith Thompson (The_Other_Keith) (E-Mail Removed) <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

Harald van =?UTF-8?B?RMSzaw==?=
Guest
Posts: n/a

 08-08-2006
Keith Thompson wrote:
> (E-Mail Removed) writes:
>> #define _(__,___)\
>> ___##__

>
> The identifiers __ and ___ are reserved to the implementation.

Even as macro arguments? On comp.std.c I was told that

#if 0
__special
#endif
int main(void) {}

and

#ifdef __special
/* nothing */
#endif
int main(void) {}

are both strictly conforming -- essentially because __special is only
reserved for "any" use after preprocessing. During preprocessing, it is
reserved for use as a macro name, but not for anything beyond that unless
it doesn't affect any (otherwise) strictly conforming program. Since naming
your macro arguments __ and ___ prevents any predefined macros __ and ___
from being expanded, I think that should be fine.

Keith Thompson
Guest
Posts: n/a

 08-08-2006
Harald van DÄ³k <(E-Mail Removed)> writes:
> Keith Thompson wrote:
>> (E-Mail Removed) writes:
>>> #define _(__,___)\
>>> ___##__

>>
>> The identifiers __ and ___ are reserved to the implementation.

>
> Even as macro arguments? On comp.std.c I was told that
>
> #if 0
> __special
> #endif
> int main(void) {}
>
> and
>
> #ifdef __special
> /* nothing */
> #endif
> int main(void) {}
>
> are both strictly conforming -- essentially because __special is only
> reserved for "any" use after preprocessing. During preprocessing, it is
> reserved for use as a macro name, but not for anything beyond that unless
> it doesn't affect any (otherwise) strictly conforming program. Since naming
> your macro arguments __ and ___ prevents any predefined macros __ and ___
> from being expanded, I think that should be fine.

You may be right; I'm not sure. (I avoid the issue by avoiding
identifiers starting with '_' altogether.)

--
Keith Thompson (The_Other_Keith) (E-Mail Removed) <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

Michael Mair
Guest
Posts: n/a

 08-08-2006
Harald van DÄ³k schrieb:
> Keith Thompson wrote:
>
>>(E-Mail Removed) writes:
>>
>>>#define _(__,___)\
>>>___##__

>>
>>The identifiers __ and ___ are reserved to the implementation.

>
> Even as macro arguments? On comp.std.c I was told that
>
> #if 0
> __special
> #endif
> int main(void) {}
>
> and
>
> #ifdef __special
> /* nothing */
> #endif
> int main(void) {}
>
> are both strictly conforming -- essentially because __special is only
> reserved for "any" use after preprocessing. During preprocessing, it is
> reserved for use as a macro name, but not for anything beyond that unless
> it doesn't affect any (otherwise) strictly conforming program. Since naming
> your macro arguments __ and ___ prevents any predefined macros __ and ___
> from being expanded, I think that should be fine.

Predefined macro names must not be the subject of a #define or
#undef directive; i.e. #define __(_,___) ___##_ would not have
been allowed as _ followed by an uppercase letter or _ belongs to
the "implementation namespace" for predefined macro names. (C99,
6.10.8#4)
Identifiers starting with _ followed by an uppercase letter or
_ are always reserved for any use, identifiers starting with
_ followed by a lowercase letter are reserved for file scope
(ordinary and tag namespace) identifiers. (C99, 7.10.3#1)
As macro names are identifiers (C99, 6.2.1#1), I'd say you are
right.

Cheers
Michael
--
E-Mail: Mine is an /at/ gmx /dot/ de address.

MQ
Guest
Posts: n/a

 08-09-2006

(E-Mail Removed) wrote:
> my friend gave this code to me..... it is working fine....how come?
>
> please explain me if u can understand.....
>
> #include <stdio.h>
> #include <conio.h>
>
>
> #define _(__,___)\
> ___##__
> _(id,vo) _8(_(
> ar,ch)a,_(ar ,ch
> )*_2){_(ile,wh) (a
> --)_(ntf, pri)("%s"
> ,_2);}_(id,vo) _1(_
> (nt,i) s,_(nt,i) n,
> _(nt,i) k=1,_(ar,ch
> ) *_3="* "){_8 ( k,
> "\n");_8(s," ");_8(
> n,_3);}_(id,vo) _6(_(nt,i) k,_(nt,i)
> l,_(ar,ch) *_9_){_8(k,"\n");_8(l, " ");_(ile
> ,wh)(*_9_)_(ntf,pri)("%c",*_9_++-12);} _(id,
> vo) _(in,ma)(){_(ar,ch) _1_1_[]="cu€" "t,nq"
> "€,~qsm~p8",_2_2_[]="X{wm";_(ar,ch) _22[]=
> {240,32,0},_4;_1(20,3,6);_1(19,1)
> ;_1(4,1,0);_1(19,1); _1(1,1, 0,
> _22);_1(1,1,0);_1(19,1);
> _1(4,1,0);_1(15,;
> _1(13,10);_1(0,1,0,"*");_
> (or,f)(_4=0;_4<4;_4++) {_1(15+_4*2,
> 8-_4*2);_(f,i)(_4==0) _1(0,2,0," *");}_(
> or,f)(_4=2;_4>=0;_4--)_1(15+_4*2,8-_4*2);_6(3,
> 26,_1_1_);_6(2,40,_2_2_);_(ile,wh)(!_(it,kbh)());}

Yikes, someone has too much spare time....

zhao.kaiyong@gmail.com
Guest
Posts: n/a

 08-09-2006

(E-Mail Removed) wrote:
> my friend gave this code to me..... it is working fine....how come?
>
> please explain me if u can understand.....
>
> #include <stdio.h>
> #include <conio.h>
>
>
> #define _(__,___)\
> ___##__
> _(id,vo) _8(_(
> ar,ch)a,_(ar ,ch
> )*_2){_(ile,wh) (a
> --)_(ntf, pri)("%s"
> ,_2);}_(id,vo) _1(_
> (nt,i) s,_(nt,i) n,
> _(nt,i) k=1,_(ar,ch
> ) *_3="* "){_8 ( k,
> "\n");_8(s," ");_8(
> n,_3);}_(id,vo) _6(_(nt,i) k,_(nt,i)
> l,_(ar,ch) *_9_){_8(k,"\n");_8(l, " ");_(ile
> ,wh)(*_9_)_(ntf,pri)("%c",*_9_++-12);} _(id,
> vo) _(in,ma)(){_(ar,ch) _1_1_[]="cu€" "t,nq"
> "€,~qsm~p8",_2_2_[]="X{wm";_(ar,ch) _22[]=
> {240,32,0},_4;_1(20,3,6);_1(19,1)
> ;_1(4,1,0);_1(19,1); _1(1,1, 0,
> _22);_1(1,1,0);_1(19,1);
> _1(4,1,0);_1(15,;
> _1(13,10);_1(0,1,0,"*");_
> (or,f)(_4=0;_4<4;_4++) {_1(15+_4*2,
> 8-_4*2);_(f,i)(_4==0) _1(0,2,0," *");}_(
> or,f)(_4=2;_4>=0;_4--)_1(15+_4*2,8-_4*2);_6(3,
> 26,_1_1_);_6(2,40,_2_2_);_(ile,wh)(!_(it,kbh)());}

If u have many spare time. u can find all the code on IOCCC. This
place u can find what u want, hah